I think the Application Blocks that MS are fabulous and they let developers build a complicated application very quickly, however, it would be great if MS could include a pre-compiled strongly named assembly in the download. Is there a reason this isn't
done?

Most of the App Blocks are designed to be guidlines, not the finished product. Because of this, you should mold them to fit in your framework by manipulating the source. So being compiled would be worthless in most places.

Glad you find the Application Blocks useful! There are a number of reasons why we initially chose the source-only route, but we are currently revisiting this decision. Although I can't promise an outcome at this stage, I can tell you that we are spending
significant effort in improving the "out of the box" experience for the next generation of the Application Blocks.